Combined gyro-compass and artificial horizon



lJue 2, 1936. i c. HAvlLL f d .2,043,168

.Tl-H E COMBINED GYRO COMPASS AND ARTIFICIAL HO'RIZON` Filed' Oct. 19, 19352 5 Sheets-Sheet 1 INVNToR.

f4 cl/A/aA//n HAV/LL.

Ju'ne`2, 1936. c. H. HAvlLL 2,043,168

COMBINED 4GYRO COMPASS AND ARTIFICIAL HORIZON y Filed oct. 19, 1932 v 's men-sheet 2 ATTORNEY,

BWWM- June 2, .1936.

` C. H. HAVILL COMBINED GYRo COMPASS ANDV'ARTIFICIAL HoRiZoN Filed 001. 19, 1952 .3 sheds-sheet s FT BANK INVENToR. L'L/NTN/HIAV/LL.

' v i ATTORNEY.

Caf

Patented June 2, 1936 3,043,168 COMBINED- Gmo-contrase AND UNITED I STATESl ARTIFICIAL HORIZON Clinton H. Havlll, South Orange. N. 1.,*assignor, -by mesne assignments, to Eclipse Aviation Corporation, East Orange, N. J., a

of New Jersey corporation Application October 19, 1932, Serial No. 638,608

y 6 Claims.- l(Cl. 33204)' The present invention relates to gyroscopic dev ices and more particularly to a combined gyrocompass and horizon indicator. i

Gyro-compasses and gyroscopic horizon indi` lsists in combining a gyra-compass and a horizon 5 cators are 'both well known in the art but the former, as constructed heretofore, are cumbersome and too expensive and, therefore, not adapted for use on aircraft where space and weight are of greatest importance and'where the cost of 'an instrument must be in reasonable proportion to the cost of the craft, while the horizon indicator, as constructed heretofore, is constituted as a separate instrument independent of the 'gyrocompass.

Accordingly, one of the objects of the present.

invention is to provide a novel instrument constituting a combined gyra-compass and horizon indicator and which is small, compact and light in weight and therefore lparticularly adapted for usey on aircraft.

Another object is to provide a novel combined gym-compass and horizon indicator whereby the compass direction of a craft lcarrying the same may be indicated simultaneously and'in the same field oi'l view with the attitude of the .craft relative to the horizon and, hence, the use of separate instruments dispensed wit 'I'he above and other objects and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description which follows when read in connection with the accompanying drawings wherein one embodiment of the invention is illustrated. Itis to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not to be construed as defining the limits of the invention, reference being had for this purpose to the appended claims.

In the drawings wherein like reference characters refer to like parts vthroughout the several views,

Fig. 1 is a front elevation of one form of instrument embodying the present invention;

Fig. 2 is a longitudinal section taken on line 2-2 of Fig. 1;

f Fig. 3 is another longitudinal section taken on line 3-3 of Fig. 1: Y

Fig. 4 is a transverse section taken on the line 4 4 of Fig. 3;

Figxis a detail view, partly in section, illustrating one arrangement for supplying uid to drive the gyro rotors of the device;

Figf is a detail perspective 'view oi' one form loi' vlinkage employed for operating the horizon indicator; and

Fig. 7 illustrates the manner in which the device of the invention indicates the attitude of the craft relativeto the horizon.y f 4 As pointed out. hereinbefore, the invention c'onindicator into a single `instrument whereby the latter may indicate both the compass direction of the craft carrying same and the attitude of th latter with respect to the horizon. A,

Referringto the drawings and more particu- 10 l \larly to Figs. 1 to 4, inclusive, the'device embodyaxis, respectively... The frame I 0, in turn, is Journaled for rotation about a vertical axis in an other frame I5, the latter being made pendulous by meansl oi' a suitable weight I6 secured to or 20 formed integral therewith. 'I'he frame I5 is arranged to swing about two horizontal transverse axes perpendicular to each other and, for this purpose, said frame I5` is journaled in a horizontal gimbal frame II, as for example, by means` of 25 4 ball bearings I8 and I8. The gimbal frame II is f also journaled at one end in a casing 20 and at its other end on av vertical support 2I bymeans of bearings 22` and 23, respectively, as shownin Figs. 2 and 3. The vertical support 2l may be secured 3o to the bottom of the casing in any suitable manner, as by screws 24.

It will be seen from the above arrangement, and as is well known to those skilled`in the artl to which this invention appertains, that as the gyro rotors 8 and 9 rotate in their bearings about the horizontal axis and the vertical axis, respectively. the rotor 8, due to the action yof the weightIB will maintain its axis always horizontal and in the north and south meridian of the earth and, 4o therefore, constitutes Va true meridian seeking compass, while the rotor S will also, with the aid of the mass I6, maintain its axis vertical in view of the fact that the frame I5 within which the azimuth frame II! is journaledis pendulously suspended by means of the gimbal frame I1, the casing 20 and the vertical support 1 I Means are now provided whereby the direction of the axis "of the rotor 8 may beindicated in terms' of compass direction, and for this purpose 50 a compass card 25 is secured to the azimuth frame y I0 in any suitable manner (not shown) so asto be rotatable therewith in .the frame I5 and in such a manner that the north and south indications on the card are'directly in line with the axis `of 55 ative position of the vertical frame I5 and casing.

2li whereby the attitude of the craft on which the casing is mounted may be indicated relative to the horizon. -As illustrated in detail in the perspective View of Fig. 6, said means comprise a pair of transverse horizontally aligned members 26 and 21 bent inwardly at right angles and secured to a frame 28 in any suitable manner, as

by means of connectingv arms 25 and 30, respectively, said frame being pivoted at 3| and 32 in vertical arms 33 and 34, respectively, which are rigidly secured to the gimbal frame I1 so that the frame 28 moves with the gimbal I1 when relative angular movement takes place between the casing 20 and the gimbal I1 about bearings 22 and 23, which movement corresponds to a movement of the craft about its longitudinal axis. The frame 28 is also pivotally connected to thevertical fram'e I5 by means of a pair of vertical arms 35 and 35, the latter having pins 31 and 38 adapted to slide in slots 31a and 38a provided in the lon- 25 and 21, which represent the horizon line, is a fixed reference member 4I carried by a bracket 42 secured to the vertical fixed support 2I in any suitable manner as by means of screws 43a and, therefore, movable with the aircraft. The reference member 4I is preferably in a form simulating the wings of an aircraft but is provided with a cut-away portion 43 through which the compass card 25 may be viewed and a reading obtained from the card by means of a lubbers mark 44 formed on an arcuate member 44a (Fig. 4) carried by the vertical frame I5, said mark being located centrally of thearcuate member` so that it may be viewed through the cut-away portion 43. It will, therefore, be apparent that when the plane dives, for example, the rear of the casing 28 will move downward, causing the frame I5 tol move to the right relatively to the casing 28 (as viewed in Fig. 3). Suchl movement of the frame I5 will move the horizon frame 28 upwardly and, hence, the horizon members 25 and 21 will also ymove upwardly, 4giving an indication such as is.

apparent to the pilot when he can see the actual f horizon, i.- e. the horizon is going up while his craft is going down,1.the craft being represented by the ilxed reference memberv4l. The reverse action takes place when the plane goes into a climb, i. e. the .horizon line 25-21 goes down while the craft, as represented by member 4I, goes up. The front of the casing 25 is closed by means of a suitable transparent member such as a cover-glass 45 secured to the casing as, for example, by means of a clamping ring 45, so that thecompass card and the horizon members 25 and 21 may be viewed from the front 'of the instrument, the latter being adapted to be secured in a known form of an artificial horizon and to an instrument panel by means of ears or lugs 41, the rear of the casing positioned in the direction of the nose of the aircraft.

Referring now to Figs. 3 and 5, the rotors 8 and 9 are adapted-to be rotated about their re- 5 spective axes by directing a jet of a suitable fluid. such as air, against a series of peripheral buckets 41 and 48 provided on the rotors 8 and 9, respectively. For this purpose there are provided a pair of nozzles, 48 and 50- (Fig'. 5) to which air is supplied through a passage 5l provided in the frame I0, which passage -is in communication with a similar passage 52 provided in the vertical frame I5. The passage 52, in turn, communicates with a passage 53 provided in the gimbal I1, and the 15 passage 53 is placed in communication with the atmosphere through a suitable stumng box 54 provided at the rear of the casing 20. In order to supply air to the nozzles 49 and 50 the casing is, preferably, exhausted in any suitable manner, 20 as by connecting the same` to a Venturi tube (not shown) by means of a coupling member 55 and upon such exhaustion of the casing air is admitted through the stufhng box 54, the passage 53, the passage 52 and the passage 5I, from the latter 25 of which the air passes to the nozzles 49 and 50 which direct the air against the peripheral buckets 41 and 48 of the rotors 8 and 9, respectively. Itwill be apparent, however, that instead of connecting the casing to a venturi by means of the 30 coupling member 55 the casing may be connected to a suitable source of positive pressure, such as a pump, by means of the stufdng box 54 so that air will be pumped into the casing and exhausted from the latter through the member 55. 3 Since the assemblage described above is pendulous it will be affected by acceleration forces acting along the longitudinal and transverse axes of the craft as well as by centrifugal forces when 'the craft is turning. The action of such forces 40 would tend to cause the frame I5 to depart from its true vertical position and, therefore, means are provided for eliminating the effects of these forces. Such means may be of the type employed 45 comprising four weights 55, 51, 58 and 59, as shown in Figs. 3 and 4, said weights being suspended in pairs from rods 58 and 5I, respectively. extending through the mass I5 at right angles to each other. The weight of each pair, however, is arranged so that it can move in only one direction on its pivoting rod, that is the weight 55 can movev only in a direction towards the plane of the paper (Fig. 3) and the weight 51 can move only in a direction from the plane of the paper', while the weights 55 and 58 move in a corresponding manner when viewed in Fig. 4. In normally vertical positions, that is when no acceleration forces are present, the weights 55, 51, 60 58 and 53 are arranged to cover openings 52, 83, 64 and 5,5, respectively, provided in the mass I8, which extend into a chamber 55, the latter being in communication with the fluid supply passage 52 by means of a connecting passage 55 so that 65 when any one of the openings is uncovered by movement of its associated weight air will be sucked into the chamber 55, thereby producing a reaction on the weight I5 in a direction opposite to the ow of air into the-chamber. For example, 7o if the opening 52 is 'uncovered by movement of the weight 55, the mass I8 will beurgedto the left as viewed in Fig. 3, and if the opening 53 is uncovered by movement of the weight 51 then the mass be urged the right as viewed in Fig. 3. A similar action takes place by operation of the weights 58 and 59 but in aplaneat right angles to the plane of the actions produced by the weights 56 and 51. However, due to the movement of the mass I6 by the reaction produced by the air entering v,the openings, the frame is caused to precess in a direction at right angles to the reaction, that is, the tendency of the mass 'i8 to move to the left in Fig. 3 will cause the frame I5 to precess in a direction towards or away from the plane 'of the paper depending upon the direction of rotation of the rotor 9. Therefore, the direction of movement of the weights 56 to 59, inclusive, should be so correlated with the direction of rotation of the rotor 9 that when acceleration or centrifugal forces act upon the weights and simultaneously upon the mass I6 the latter will be caused to precess in a direction opposite to that which the acceleration or centrifugal forces are acting, thereby maintaining said mass in a true verticalposition at all times irrespective of the presence of any such disturb,- ing forces. Although the reaction forces acting on the mass I6, and hence the frame I5, will also cause a slight precession of the compass frame I0 due to the gyroscopic action of the rotor 8,-

thus tending to disturb the azimuth indication of the compass, nevertheless, such disturbances are only momentary and present only during an acceleration or deceleration and/or turning of the craft upon which the device isrnounted and,

therefore, the rotor 8 will again align itself with the plane of the meridian as soon as the craft is in level flight. l

Referring to Fig. '7, there are shown several of the indications which may be produced by' the instrument embodying the invention for various attitudes of the craft with respect to the horizon as, for example, level flight, right bank, left bank,

vclimb and descent. Of course various combinations of movements will be indicated accordingly. f n

FreniV the foregoing it will be seen that, due to the whole assemblage being pendulous and maintained in a true vertical position at all times by the action of the rotor 9 and the action of means for eliminating acceleration and centrifugal effects, the gyro rotor 8 will cause the compass card 25 which is carried thereby to indicate the compass direction of the craft on lwhich the device" is mounted, and the horizontal members 26 and 21 carried by the frame 28 will give indications of the attitude of the craft with respect to the horizon, thus providing a single instrument embodying a novel structure whereby yboth indications may be viewed simultaneously in a single view and, hence, making it unnecessary for the pilot to direct his attentionfalternately to two separate instruments.

Although only one embodiment of theinvention has been illustrated and described in detail,

various changes in the form and relative arrange-F spin axis of the gyroscope, a fixed support. means pendulously mounting said second frame on said support for angular( movement about two horizontal axes perpendicular to each other whereby said first frame is caused to precess in the second frame until the axis of the horizontal gyroscope is aligned parallel to themeridian, a compass .card carried by said rst frame, allubber mark carried by the second frame and cooperatving with the compass card to indicate the azimuth position of the fixed support relative to the meridian, means pivotally connected to said second fra-me and said mounting means therefor, indicating means operated by said last-meng tioned means for movement in synchronism with said second frame relative to the fixed support,v

and a reference index carried 'by the fixed support and cooperating with said indicating means to indicate the attitude of the fixed support with respect to the true horizon.

2. In combination, a frame, a pair of gyroscopes journaled in said frame and adapted for rotation about a horizontal axis and a. vertical axis, re-

spectively, said axes being fixed relatively to said frame, a second frame, said first frame, being journaled in said second frame for rotation about a vertical axis, a weight on theBlower part of said second frame, a fixed support, means pendulously mounting said second frame said gyros and said" first frame on said fixed support for angular movement about two vhorizontal axes perpendicular to each other whereby said first frame is caused to precess in the second vframe by the action of the weight until the axis of the horizon- A ta'l gyroscopeis aligned parallel to the meridian, means associated with said weight for eliminating 35 the eiects of undesirable disturbing forces on said pendulous gyroscope frame,a compass card carried by said first frame and cooperating with a lubber mark carried by the second frame for indicating the direction of travel, and means operatively connected to said secondvframe and the mounting Ifor indicating the kangular position of the second frame with respect to the xed support.

3.In combination, a' casing, a framewithin said casing, two gyroscopes mounted in said frame with their spin axes horizontal and vertical, respectively, and relatively fixed insaid frame, a second frame supporting said first frame for `pre'cession about a vertical axis coinciding with Y the axis of 'the vertical gyroscope, a gimbal support carried by the casing for pivotally supporting the second frame the ilrst frame and the gyros for relative movement about Atwo horizontal axes perpendicular to each other, means including a continuous passage from the exterior of thevcasing through the gimbal support, the second frame and the first frame for directing a flidunder pressure against the peripheries of the gyroscopes for driving the latter, means for making the second frame pendulous whereby the horizontal gyroscope is caused to precess until its axis is in the earths meridian and the vertical gyroscope is effective to maintain a true vertical position, and means operatively associated with said frames for respectively indicating the positions of the axes of said gyroscopes relative to the meridian and to a plane parallel to the earths surface.

4. In combination, an instrument casing adapted for mounting-on a substantially verticalv instrument panel and having a cover glass at the front thereof, a. pair of gyroscopes mounted -in said casing with their spin axes horizontald vertical, respectively, gimbals in said casing and carrying said gyroscopes forsimultaneous movement of their spin axes about two mutually pering means for eliminating the eiects of unde-4 sirable disturbing forces on said gyroscopes, a compass card controlled by said horizontal gyroscope and viewable through the cover glass of the casing for indicating the true meridian, and indicating means controlled by the vertical gyroscope i and also viewable through the cover glass for indicating the-true horizontal plane in the ileld of view of and coincidentally with the periphery of the compass card so that substantial horizontal Valignment of said compass card and said indicating means indicates that the spin axis of the horizontal gyroscope is in a plane parallel to the earth's surface.

5. A combined horizon indicator and gyrocompass for aircraft, comprising a nxed support, a frame, a gyroscope mounted in said frame with its spin axishorizontal, a second gyroscope mounted in said frame with its spin axis vertical, means including said frame and providing a gimbal mounting for said gyroscopes on said fixed support to permit simultaneous movement of the spin axes of said gyroscopes about two mutually perpendicular horizontal axes relative to said fixed support and to permit precession of the spin axis of the horizontal gyroscope in azimuth, a compass card controlled by said horizontal gyroscope and movable therewith upon precession thereof, an indicator controlled by said vertical gyroscope, and a common reference member against which said compass card and indicator are correlated so that coincidence of the card, the indicator, and the reference member along a horizontal line indicates level ight in a direction shown on the compass card by the reference member.

6. In combination, an instrument casing adapted for mounting on a substantially vertical instrument panel and having a cover-glass at the front thereof, a pair of gyroscopes mounted in said casing with their spin axes horizontal and vertical, respectively, gimbals in said casing and carrying said gyroscopes for simultaneous move- 'vertical and the horizontal gyroscope as a true meridian-seeking compass, and indicating means directly controlled by said gyroscopes and viewable through the cover-glass of the casing for indicating the true meridian and the true horizontal plane. CLINTON H. HAVILL. 

